It did not include VOIP elements built into other products such as multiservice switches.

VOIP typically is less expensive to provide and lends itself to new features such as click-to-dial and unified voice and e-mail messaging.

Traditional carriers have rolled out services such as Verizon Communications's VoiceWing but have not marketed them aggressively, Raab said. They would rather keep customers on the existing PSTN (public switched telephone network) in which they have so much already invested.

"They want to have a competitive solution, but they don't want to push the transition now," Raab said.

Established carriers are carrying more voice calls but will eventually replace their circuit-switching technology with VOIP, but that older equipment has depreciation cycles as long as 30 years, Raab said.